perf: add createDeepNestedDocArray benchmark re: Automattic#14897

Author: vkarpov15

benchmarks/createDeepNestedDocArray.js

@@ -0,0 +1,37 @@
+'use strict';
+
+const mongoose = require('../');
+
+run().catch(err => {
+  console.error(err);
+  process.exit(-1);
+});
+
+async function run() {
+  await mongoose.connect('mongodb://127.0.0.1:27017/mongoose_benchmark');
+
+  const levels = 12;
+
+  let schema = new mongoose.Schema({ test: { type: String, required: true } });
+  let doc = { test: 'gh-14897' };
+  for (let i = 0; i < levels; ++i) {
+    schema = new mongoose.Schema({ level: Number, subdocs: [schema] });
+    doc = { level: (levels - i), subdocs: [{ ...doc }, { ...doc }] };
+  }
+  const Test = mongoose.model('Test', schema);
+
+  if (!process.env.MONGOOSE_BENCHMARK_SKIP_SETUP) {
+    await Test.deleteMany({});
+  }
+
+  const insertStart = Date.now();
+  await Test.create(doc);
+  const insertEnd = Date.now();
+
+  const results = {
+    'create() time ms': +(insertEnd - insertStart).toFixed(2)
+  };
+
+  console.log(JSON.stringify(results, null, '  '));
+  process.exit(0);
+}